Process of reducing the shrinkage and felting tendencies of protein textile materials



-wearability of the fabric.

Patented Oct. 11, 1949 2,484,599 v v I PROCESS OF REDUCING THE SHRINKAGE AND FELTING TENDENCIES QF PROTEIN TEXTILE MATERIALS Mark Wcisberg, Providence, Archibald S. Stevenson, Pawtucket, and Leo Beer, Providence, R. L, asslgnors to Alrose Chemical Company, Craneton, R. 1., a corporation of Rhode Island No Drawing. Application June 6, 1945, Serial No. 597,954

pecially woolen fibers, alone or in mixture with cellulosic fibers such as cotton or rayon in various proportions to reduce their shrinkage and felting tendencies. Other natural or modified protein fibers other than wool however are suitable. The treatment may take place at any stage of fabric manufacture, namely in the stock, skein or in the woven or the knitted piece.

The normal fabrics made from the aforesaid fibers and mixtures containing the same have a marked yet normal tendency, after successive washing and cleaning with aqueous soap solutions, to shrink in different degrees; this affects the Wool fabrics, upon repeated washings at temperatures of 100 F. to 120 F. shrink sometimes until the fabric felts and becomes unsuitable for further use.

Fabrics containing wool do not lend themselves to compressive shrinkage, or other mechanical shrinkage, as these fabrics show a tendency to shrink after each and every washing operation, especially if the operation takes place at temperatures over 100 F. Accordingly, almost without exception, the proposed processes have been based on a chemical treatment.

The most widely employed chemica1 processes for shrinkage control of protein textile materials are more or less based on the formation within the fiber of an insoluble resin. It is a matter of record that hitherto urea-formaldehyde or alkylol urea-formaldehyde condensation products have not been able to produce the desired measure of shrinkage and felting control when applied to wool, then heat treated to make insoluble.

Recently melamine formaldehyde resins and alkylated melamine formaldehyde precondensate resins have been recommended to overcome this natural tendency for wool to shrink and felt. In using this type, the woolen goods were exposed to a high, dry temperature because it was considered necessary for the impregnated fabric, after preliminary drying, to be baked or cured to produce the conversion of the soluble precondensate thereon into the insoluble form. The temperature which has been recommended was 800 F.

Generally speaking there has been an aversion to exposing woolen goods to such a high temperature. Moreover, the hand produced after application of the melamine resin drying and baking varies from a more or less crisp hand to one which is actually harsh. Being a naturally soft material, a harsh hand in a finished piece of wool is very often undesirable and sometimes even objectionable.

8 Claims. (Cl. 117-141) In the conventional treatment to deter shrinkage and felting, wherein urea-formaldehyde or melamine-formaldehyde condensation products have been employed, the aqueous impregnating solution. of either of these water-soluble condensates also contained a free acid or salts which liberated free acid in the drying or baking steps or both. The acids used for this purpose were for instance boric-or lactic acid; and the salts were NH4CI or (NHO2S04 or (NH4)2HPO4, etc. After the impregnation, the fabrics were squeezed thoroughly, dried at a moderate temperature, then cured or baked.-

This last step has always been considered the most important or critical of such processes. The role of the catalyst, referred to supra, is to shorten the process so that the length of time of the reaction will not be of such a duration that production will be seriously hampered. Baking" or curing-is a term designating heating the impregnated goods in a dry heat ranging from 250 F. to 300 F. or even higher to insolubilize the resin. There is always the possibility of under-baking with certain known disadvantages or over-baking with its attendant disadvantages, known to everyone who is familiar with the art and use of this type of process.

We have found out'that not alone can the aforesaid disadvantages in the operation of this process be eliminated but that excellent shrinkage control and marked felting control of wool and other protein textile materials can be secured by replacing the dry high temperature baking by a steaming operation in an atmosphere of a steamvolatile acid, to convert the water-soluble precondensate to a water-insoluble condensation product. Hence, according to our process, the goods are impregnated with an aqueous solution of water-soluble precondensate of urea and formaldehyde or alkylated urea-formaldehyde such as methylated urea-formaldehyde, or melamine-formaldehyde or alkylated alkylol melamine such as methylated methylol melamine, squeezed, dried at moderate temperature, then steamed through a steam chamber of ager in an atmosphere of an excess of volatile acid. There should be an excess of free volatile acid present at all times during the steaming step. It is obvious that there is a corresponding reduction in time of cure with increase of temperature. The condensation product becomes water-insoluble in this step and this change governs the minimum time required.

The aqueous solution of precondensate preferably cloes not contain any acid or salt catalyst which liberates acid upon heating. Such solutions with acids or acidic salts are stable or and felting properties.

usable for only a limited period of time. is the acidic condition causes polymerization of the precondensate resin and therefore such solutions are consequently of no further use for im resnating the textile fabric. Moreover the resulting shrinkage eflects when an acidic catalyst is not added are actually superior to those when an acidic catalyst is employed.

As has been pointed out supra, this steaming operation is also adapted for use with the melamine-formaldehyde or alkylated alkylol melamine resins, but results show that no advantage is to be gained by the use of the more expensive melamine types of resins in place of the less expensive urea-formaldehyde resin types.

Organic acids are the preferred acids but steam-volatile inorganic acids can be employed. The organic acids are not limited as to type, and embrace the aliphatic, aromatic, alkyl-aryl acids and derivatives which are steam volatile. Ex-

amples thereof are: formic, acetic, propionic, v

butyric, diethylacetic, benzoic and toluic acids. Examples of volatile inorganic acids are the hydrogen halides, of which hydrochloric acid is the best known commercially. However the use of an inorganic acid might be attended with certain disadvantages well known to the man familiar with such a process as the one in question, and such disadvantages practically prohibit the use of the said acids.

The temperature of steaming is substantially 212 F. or above. The preferred range is 212- 220 F. Temperatures of 250 F. or above tend to damage protein fibers. The period of time corresponding to the preferred range is 5 to 8 minutes. with temperatures above 220 F. the time can be less than 5 minutes.

While of course a minimum period of time is required for the reaction, no harm will accrue to the fabric even if it is exposed to the acid steaming step for a much longer period. In other words there is a time-margin which takes from this steaming all the critical features of the curing step used in the orthodox or conventional process of shrinkage control.

After the steaming step, the goods should be washed and soaked, rinsed in warm, then cold water, and finally dried.

Wool or other protein fabrics treated in this way possess very significant reduced shrinkage They also retain a soft hand which is important particularly for such fibers. They are also not impaired in their tensile strength or in their resistance against abrasion. On the contrary the latter quality is enhanced.

For the purpose of more clearly establishing the point of the superiority of applicants textile process, and particularly the preferred method mentioned in the preceding paragraphs. as compared to the conventional process referred to supra, the results of a series of tests will be presented.

The following table shows the results on wool cloth, wherein standard tests on the goods were made. The samples selected were 100% wool flannel.

The figures in the vertical columns represented by the designations sample No. 1, sample No. 2 and sample No. 3, respectively, correspond to measurements on samples subjected to the respective treatments as described below.

The solution which was used for treatins sample No. 1 was formed from 120 grams of liianaset (75-80%) dissolved in water and diluted to 1 liter with water. The solution which was used for treating sample No. 2 was formed from 120 grams of Lanaset" (75-80%) and 3 grams of (N34) aHPOi dissolved in water and diluted to 1 liter with water. The solution which was used for treating sample No. 3 was formed from grams of urea-formaldehyde precondensate resin, in powdered form (a commercially available product) dissolved in water and diluted to 1 liter with water.

The swatches of wool fabric designated No. 1, No. 2 and No. 3, respectively, were impregnated with the above described solutions, making certain that complete wetting out of the fabric had taken place, squeezed, allowing a pick-up of 100% on the dry weight of the goods, then dried at substantially 120 F. The patches No. 1 and No. 3 were then steamed in a steam chamber in the presence of an excess of formic acid for a period of about 5 minutes at a temperature of substantially 212 F. Swatch No. 2 was dry heat-cured for 6 minutes at 300 F. After these aforesaid designated heat treatments had converted the water-soluble type precondensates of the alkylated melamine-formaldehyde resin and the ureaformaldehyde resin to the insoluble form, the swatches were washed, and soaped for 5 minutes at 100 F., rinsed with warm then cold water, and finally dried.

After drying the swatches were marked in order to measure the shrinkage resulting from consecutive washes.

After each washing carried out at F. for 10 minutes in a laundry tumbler washing machine, the swatches were rinsed for 5 minutes in water at F.,.then rinsed in cold Water for another '5 minutes. The goods were then removed from the machine, packed between towels, and after 10 minutes pressed in a laundry pressing machine until dry.

The swatches were allowed to'condition, after which they were measured. The results were as follows:

Table Sample No. 2 Treated by Solution (Lanaset, plus Catalyst) Sample No. 3 Treated by Solution (Urea-Formaldeh do. no Cat yst) Sample No. 1 Treated by Solution (Lanaset, no Catalyst) Original (Untreated Goods) BHRINKAGE Percent Percent Percent 5th Wash.

TENSILE STRENGTH warp a2 35 Filling... 31

ABRASION (IN oYcLEs) ;.i.he abrasion results were obtained by the Taber mac as.

From the results of the table it will be seen that, as compared to the untreated goods, (1)

Lanaset, according to T.-M. 412,009, registered by American Cyana'mid Co., is for Alkylated methylol melamiais for the shrinkage control of wool and woolen mixed go is.

each underwent practically no shrinkage the initial wash; (3) the swatches so treated displayed a tensile strength within 1 unit of that of the untreated, hence the tensile strength can be considered unimpaired; (4) the abrasion reand felting tendencies of a protein textile material, the steps of impregnating a. protein textile material with an aqueous solution of a watersoluble pre-condensate of the group consisting of urea-formaldehyde, melamine-formaldehyde and their ethers in the absence of an acidic catalyst, mechanically removing surplus liquid \from the materiaLdrying it, thereafter expos-' ing the impregnated textile material to steam sistance was even 225 units higher than that of in an atmosphere consisting of steam-volatile the untreated swatch. which represents a 31% increase. In comparing (a) the swatch treated by the melamine-formaldehyde precondensate resin without the catalyst, then steamed, with (b) the swatch treated by this same resin in the presence of the acidic catalyst but thereafter baked or dry-cured. the former proved to be the equal of the latter. Most significant, however, is the fact that the figures in the right hand column show that woolen fabrics treated with urea-formaldehyde without using an acidic catalyst but by said subsequent acidic steaming operation gave entirely satisfactory results in shrinkage control and non-felting. They were the equal of the results wherein the melamineformaldehyde precondensate resin was employed under the same conditions; this holds true as to each of the standard tests, namely shrinkage, tensile strength and abrasion.

Using this cheaper resin with our process. which resin has been unsatisfactory from both aspects upon wool when employing the conven tional dry, high temperature baking, results the equal of the melamine-formaldehyde have been secured. It was entirely to be unexpected that either urea-formaldehyde could be used to secure shrinkage control and non-felting of wool or that quantitative measurements by standard tests would show that it could be made toequal the melamine-formaldehyde resins on this fiber.

It will be realized by those skilled in the art that changes may be made in the processes here inbefore described without departing from th) scope of this invention. We do not intend to be bound except by the scope of the appended claims. In the claims the word "solution" 11- eludes not only a true solution but also a co. loidal solution or suspension. The term wool textile material in the claims includes wool and wool containing fabrics at any stage of fabric manufacture embracing fibers. stock, skein or in the woven or the knitted piece, etc., whether of all wool or part wool and part cotton, rayon, etc. in various proportions. And the term protein textile material" has a similar significance with respect to this broader or generic word protein.

We claim:

1. In the process of reducing the shrinkage and felting tendencies of a protein textile material, the steps of impregnating a protein textile material with an aqueous solution of a water-soluble pre-condensate of the group consisting of ureaformaldehyde, melamine-formaldehyde and their ethers in the absence of an acidic catalyst, mechanically removing surplus liquid from the material, drying it, thereafter exposing the impregnated textile material to steam in an atmosphere consisting of steam-volatile organic acid at a temperature in the range of 212-substantially 220 F. for a period of substantially 5 to 8 minutes inclusive until the condensate has become water-insoluble.

2. In the process of reducing the shrinkage with an aqueous solution of a water-soluble precondensate of the group consisting of ureaformaldehyde. melamine-formaldehyde and their ethers in the absence of an acidic catalyst, mechanically removing surplus liquid from the material, drying it, thereafter exposing the impregnated textile material to steam in an atmosphere consisting of steam-volatile organic acid at a temperature in the range of 212- substantially 220 F. for a period of substantially 5 to 8 minutes inclusive until the condensate has become water-insoluble.

4. In the process of reducing the shrinkage and felting tendencies of wool textile material, the steps of impregnating wool textile material with an aqueous solution of a water-soluble precondensate of the group consisting of ureaformaldehyde; melamine-formaldehyde and their ethers in the absence of an acidic catalyst, mechanically removing surplus liquid from the material, drying it, thereafter exposing the impregnated textile material to steam in an atmosphere consisting of steam-volatile organic acid at a temperature in the range of 212 F.- substantially 220 F. for a period not to exceed substantially 8 minutes until the condensate has become water-insoluble.

5. In the process of reducing the shrinkage and felting tendencies of a protein textile material, the steps of impregnating a protein textile material with an aqueous solution of a watersoluble pre-condensate of the group consisting of urea-formaldehyde, melamine-formaldehyde and their ethers in the absence of an acidic catalyst, mechanically removing surplus liquid from the material, drying it, thereafter exposing the impregnated textile material to steam in an atmosphere consisting of acetic acid at a temperature in the range of 212-substantially 220 F. for a period of substantially 5 to 8 minutes inclusive until the condensate has become waterinsoluble.

6. In the process of reducing the shrinkage and felting tendencies of a protein textile material, the steps of impregnating a protein textile material with an aqueous solution of a watersoluble pre-condensate of the group consisting of urea-formaldehyde, melamine-formaldehyde and their ethers in the absence of an acidic catalyst, mechanically removing surplus liquid from the material, drying it, thereafter exposing the impregnated textile material to steam in an atmosphere consisting of formic acid at a temperature in the range of 212-substantially 220 F. for a period of substantially 5 to 8 minutes inclusive until the condensate has become waterinsoluble.

7. A protein textile material resistant to shrinkage and felting. and whose tensile strength and abrasion resistance is unimpaired, impregnated throughout with a water-insoluble condensation product of the group consisting of urea iormaldehyde, melamine-iormaldehyde and their ethers,,said textile material having been impregnated with an aqueous solution of a water-soluble precondensate oi the J group consisting of urea-formaldehyde, melamine-tormaldehyde and their ethersin the absence of an acidic catalyst. mechanically removing surplus liquid from the material. drying it, thereafter exposing the impregnated textile material to steam in an atmosphere consisting oi steam-volatile organic acid at a temperature in the range of 212 F.-substantlally 220 1". tor a period not to exceed substantially 8 minutes until the condensate has become water-insoluble.

8. A wool textile material resistant to shrinkage and felting, and whose tensile strength and abrasion resistance is unimpaired, impregnated with a water-insoluble condensation product of the group consisting of urea-formaldehyde, melamine-formaldehyde and their ethers, said textile material having been impregnated with an aqueous solution of a water-soluble precondensate 'ot the group consisting of urea-formaldehyde,

melamine-formaldehyde and their" ether: in the absence of an acidic catalyst, ly removing surplus liquid from the material. drying it, thereafter exposing the impregnated textile material to steam in an atmosphere consisting of steam-volatile organic acid at a temperature in the range oi 212 lit-substantially 220' I". (or a period not to exceed substantially B'minutes until the condensate has become water-insoluble.

MARK ARCHIBALD S. STEVENSON.

LEO BEER.

REFERENCES CITED The i'ollowing references are of record in the v iile oi this patent:

UNITED STATES PATENTS Number Name Date Re. 22,566 Johnstone et a1 Nov. 21, 1944 2,088,227 Battye et a1 July 2'1, 193'! 2,191,362 Widmer Feb. 20, 1940 2,235,141

Dreyfus et al 18, 1941 

